The present invention relates to a tape winding apparatus used mainly for winding an insulating tape around the coil conductor of a rotary machine and, more particularly, to the one with a mechanism for automatically providing an optimum winding angle as required.
It is common practice that the coil of the rotary machine is insulated by an insulating tape wound many times around the coil. In this case, the tape is wound while advancing its winding position by a given distance (called a pitch) each time the tape is wound one time. At this time, it is necessary to wind the tape with a given angle of inclination. The angle of inclination of the tape depends on the diameter of a body around which the tape is wound. Therefore, as the tape is wound so as to be multilayered, the angle of inclination gradually changes, even if the same body is used.
In FIG. 1a illustrating the case of a fine body (1), the angle of the tape-winding of the body (1) is designated by .alpha., and in FIG. 1b illustrating the case of a thick body (1), the tape-winding angle is designated by .beta.. As the tape is progressively wound and reaches the end of the body (1), the winding direction of the tape is reversed and its winding continues. In this case, the winding angle must be changed to be -.beta.. In the figure, (P) designates the pitch.
In general, a tape winding apparatus winds the tape around a spool or the like and around the body, revolving it around the axis of the body while advancing its winding position along the axis at a given speed. At this time, the tape rotates around the body while at the same time turning (revolving) spirally. The distance that the winding tape advances along the axis for each revolution of the winding tape is coincident with the pitch. For this reason, the tape winding apparatus is generally provided with a mechanism for turning the winding tape and another mechanism for moving the former one along the axis of the body. In the tape winding apparatus with such a construction, if the tape winding is accomplished with insufficient pulling of the tape, the tape-wound body takes on a furrowed outer appearance. More adversely, when the tape is additionally wound on the upper layer of the furrowed tape-wound body, there occurs a slippage in the winding. Such facts are very disadvantageous. Therefore, the tape winding must be conducted with sufficient pulling of the tape. Various methods for stably giving a sufficient tension to the tape being wound, have been proposed. When the tape is wound with sufficient tension being applied thereto, if the angle of inclination of the delivering or feeding tape at the tape-feeding portion is not coincident with the tape-winding angle with respect to the body, the tension developed at the tape winding is disproportionately concentrated on only one side of the tape. Therefore, the tape is likely to be torn or broken off. It is for this reason that the tape winding apparatus is so designed that the tape is delivered with sufficient tension and the coincidence of the inclination angle of the tape being taken out with the tape winding angle.
In a conventional tape winding apparatus, the tape feeding portion is mounted with its entire of inclination, as shown in FIG. 2, for example. In the figure, (1) designates a body around which the tape is wound, (1a) designates a portion of the body where the tape has superposedly been wound from right to left, and (1b) designates another portion of the body where the tape is being wound on the portion (1a) from left to right. Reference numeral (2) designates a tape and numeral (2a) a winding tape. The winding tape (2a) is mounted through a winding-angle providing mechanism to a base member (3) revolving around the axis of the body (1) in order that it is rotatable by a supporting member (5). The winding-angle mechanism (4) is comprised of a mounting member (4b) pivotable with respect to the base member (3) by means of a hinge (4a), a bolt (4c), and a fixed nut (4d). The tape winding tension is produced by a reaction generated when the tape is fed from the wound tape (2a) due to friction between one edge surface of the wound tape (2a) and a pressure plate (5b) pressed by a spring (5a) and the supporting member (5) attached to the mounting member (4b).
In the conventional tape winding apparatus thus constructed, when the tape winding angle (.alpha.) coincides with the mounting angle (.theta.) of the wound tape, the same tension is produced at both edges of the tape in the tape length ranging from the wound tape (2a) to the tape winding point, thus minimizing the occurance of cutting the tape and providing a stable taping. The mounting angle (.theta.) of the wound-tape may smoothly be fine-adjusted with a construction that the entire mounting portion rotates around the hindge (4a) by adjusting the fixed nut (4d) of the winding angle providing mechanism (4). In this manner, the winding angle (.alpha.) is made to coincide with the wound-tape mounting angle (.theta.).
As previously stated, the tape-winding angle (.alpha.) changes depending on the diameter of the tape wound body (1). Accordingly, the angle changes when the direction of the winding direction changes or the superposing frindge of the tape changes. Therefore, the conventional tape winding apparatus must adjust the mounting angle (.theta.) by the fixed nut (4d) to coincide with the winding angle (.alpha.). The failure of the adjustment brings about cutting of the tape so that the adjustment work is complex.